Sequential cutting of Urochloa brizantha cv. MG 5 changes flowering season and seed production components

Tiago Aranda Catuchi,Elton Anderson Aranda,Gabriel Chaves Parmezan,Fabiana Lima Abrantes,Ceci Castilho Custódio,Fernando Vinicíus Bressan,Carlos Sérgio Tiritan

doi:10.1590/0103-8478cr20200912

Tiago Aranda Catuchi, Elton Anderson Aranda + Show 5 more

Open Access

https://doi.org/10.1590/0103-8478cr20200912

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Journal: Ciência Rural	Publication Date: Jan 1, 2022
Citations: 1	License type: CC BY 4.0

Affiliation: Universidade do Oeste Paulista

Abstract

ABSTRACT: In tropical grass seed production fields, reducing plant size can increase the solar radiation to the base of the plant canopy and improve the quantity and quality of the seeds produced. This research studied the responses of the production components, the productivity, and the seed quality of U. brizantha cv. MG-5 to different canopy sequential cuttings under cultivation conditions in rain fed systems. Two experiments were carried out (agricultural year 2015/16 (s1) and 2016/17 (s2)) in a randomized block experimental design with four repetitions. The treatments consisted of sequential cut-off, indicating the month of the last cut and the agricultural year: for the 2015/16 agricultural year: Aug - s1, Sep - s1, Oct - s1, Nov - s1, Dec - s1, Jan - s1, and Feb - s1; for the 2016/17 agricultural year: Aug - s2; Set - s2; Nov - s2; Dec - s2; Jan - s2, and Feb - s2. Plant growth biometrics, seed quality variables, and productivity were evaluated. The sequential cut strategy increased the productivity and quality of pure seeds when the final cuts were done between November and December. Cuts performed after December increased the reproductive components. However, in the region in question, rainfall levels compromised seed filling; and therefore productivity and quality since the flowering of these cuttings (January and February) occurs in May.

Highlights

Brazil is the largest producer of tropical fodder plant seeds, especially Urochloa brizantha
The demand for tropical forage seeds will grow in the coming years, driven by exports to Africa, Australia, and Latin America, mainly for seeds used in crop–livestock integration systems and in pasture reform areas that are in the process of degradation (GARCIA et al, 2013; CECATO et al, 2014; BATELLO et al, 2017; CATUCHI et al, 2019)
This shortfall is reflected in the early senescence of the leaves and the low activity of the growth point, but the activity of the growth point is responsible for making the vegetative tiller reproductive (GARCEZ NETO et al, 2002; TAIZ et al, 2017)

Summary

Introduction

Brazil is the largest producer of tropical fodder plant seeds, especially Urochloa brizantha Among the cultivars of Urochloa brizantha, MG-5 is characterized by high forage production, with approximately 18 t of dry matter ha-1 year -1, and an average height of 1.6 m (PIRES, 2006) These characteristics of high forage yield potential result in low seed productivity because, due to the plant size (1.6 m), the tillers emitted at the bottom of the plant canopy received limited solar radiation for photosynthesis. This shortfall is reflected in the early senescence of the leaves and the low activity of the growth point, but the activity of the growth point is responsible for making the vegetative tiller reproductive (GARCEZ NETO et al, 2002; TAIZ et al, 2017). In perennial forage plants, the buds that differ in reproductive tillers are located at the base of the plant, so the lowering of the plants by mechanized cutting can enhance the productivity and quality of seeds, as it reduces apical dominance and increases the solar irradiation to the lower canopy, producing tillers of similar age and basal leaves with a higher photosynthetic rate (HOPKINSON et al, 1998; GARCEZ NETO et al, 2002; HARE, et al, 2007)

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